Polarization mode dispersion (PMD) is one of the main obstacles to the deployment of high-speed long-haul optical communication systems, especially systems with bit rates of 40 Gb/s per-channel and higher. To overcome PMD limitations, optical PMD compensators (PMDCs) are used, which is adaptively adjusted to compensate PMD in the communication systems. An optical PMDC usually consists of several polarization controllers (PCs) and delay lines (birefringence elements). As PMD is not a static phenomenon but fluctuates randomly with time due to temperature changes and mechanical vibrations, a PMDC also comprises feedback signal generator and control electronics to dynamically adjust PCs and delay lines.